I currently have a Nexus 7 with the default "out-of-the-box" Android Stock OS (as of this post JB 4.2.2).

From what I've read online, Ubuntu has made a mobile version of their OS. Usually, they specially demo their mobile OS with Google's Nexus devices.

I would like to try Ubuntu on my Nexus 7, but don't want to do it permanently. Though, I still want to have the experience as if Ubuntu runs the tablet, and not Android (Just to try something new and a change of pace).

I wanted to know that if I were to permanently to install Ubuntu on my Nexus 7 device, if and how would I get my device back to the stock Android OS that came with it "out-of-the-box"?

In other words, I know you are able to install Ubuntu on Android, but is it possible, once you have cleared Android off, and only Ubuntu exists, to go from Ubuntu back to Android?

Maybe I don't know enough about what happens when you install Ubuntu on an Android device, but if there is some detail that you feel is missing, please feel to fill in the blanks of my stupidity.